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Ch 7 Circular Motion Pretest

Terms in this set (31)

When an object is moving with uniform circular motion, the object's tangenital speed
is constant
When an object is moving with uniform circular motion, the centripetal acceleration of the object
is directed toward the center of motion
What term describes a change in the speed of an object in circular motion?
tangenital acceleration
What is the term for the net force directed toward the center of an object's circular path?
Centripetal force
Which of the following can be a centripetal force?
All of the above
The centripetal force on an object in circular motion is
In the plane of the object's motion and perpendicular to the tangenital speed.
The centripetal force on an object in circular motion is
in the same direction as the centripetal acceleration
When a car makes a sharp left turn, what causes the passengers to move toward the right side of the car?
Inertia
A ball is whirled o a string, then the string breaks. What causes the ball to move off in a straight line?
Inertia
Tides are caused by
differences in the gravitational force of the moon at different points on Earth
If you lift an apple from the ground to some point above the ground, the gravitational potential energy in the system increases. This potential energy is stored in
the gravitational field between Earth and the apple.
An object's tendency to resist acceleration is measured by the object's
inertial mass.
In this text, which of the following symbols represents the constant of universal gravitation?
G
Which of the following equations expresses Newton's law of universal gravitation?
Fg = G(m1m2 / r2)
When calculating the gravitational force between two extended bodies, you should measure the distance
from the center of each body
Until the middle of the 16th century, most people believed ____ was at the center of the universe?
Earth
In the figure above, according to Kepler's law of planetary motion
if change in t1 is equal to the change in t2, then a1 is equal to a2
The equation for the speed of an object in circular orbit is vt = root (G(m/r)). What does m represent in this equation?
The mass of the central object?
Which of the following quantities measures the ability of a force to rotate or accelerate an object around an axis?
Torque
Where should a force be applied on a lever arm to produce the most torque?
Farthest from the axis of rotation
If you want to open a swinging door with the least amount of force, where should you push on the door?
As far from the hinges as possible
What kind of force provides the centripetal force on the bicycle?
Friction
Why does an astronaut weight less on the moon than on earth?
The gravitational field strength is less on the moon's surface than on Earth's surface
Which of the following confirms that gravitational mass and inertial mass are equal
Free-fall acceleration is the same at all points where the gravitational strength is the same.
The gravitational force between two masses is 36N. What is the gravitational force if the distance between them is tripled?
4.0N
Two small masses that are 10.0 cm apart attract each other with a force of 10.0 N. When they are 5.0cm apart, these masses will attract each other with what force?
40.0N
How would the speed of Earth's orbit around the sun change if Earth's distance form the sun increased by 4 times?
It would decrease by a factor of 2.
How would the speed of Earth's orbit around the sun change if Earth's mass increased by 4 times?
The speed would not change.
When an astronaut in orbit experiences apparent weightlessness,
the net gravitational force on the astronaut is not balanced by a normal force
If you cannot exert enough force to loosen a bolt with a wrench, which of the following should you do?
Use a wrench with a longer handle
Suppose a doorknob is placed at the center of a door. Compared with a door whose knob is located at the edge, what amount of force must be applied to this door to produce the torque exerted on the other door?
Two times as much.
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